Vortex flowmeter including pressure pulsation amplitude analysis

ABSTRACT

A configuration tool is for a vortex flowmeter having a flowtube, a bluff body positioned in the flowtube for shedding vortices in the fluid, and a pressure sensor configured to obtain a signal indicative of a time-varying fluid pressure having an oscillation associated with the vortices. The configuration tool includes a processor that determines a type of fluid flowing through the flowtube based on the amplitude of the oscillation. The processor sets a fluid-type setting of the vortex meter to match the determined type of fluid. An alarming system for a control system including such a flowmeter includes a processor that assesses a density of a fluid flowing through the flowtube based on the amplitude and compares the assessed density to a fluid density configuration setting. The processor activates an alarm if the difference between the assessed density and the fluid density configuration setting exceeds a threshold.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.14/532,542, filed Nov. 4, 2014, the entire disclosure of which isincorporated herein by reference.

FIELD

The present invention relates generally to vortex flowmeters.

BACKGROUND

Flowmeters may measure the rate of flow of a fluid in a pipe or otherpathway. The fluid may be, for example, a gas or a liquid, and may becompressible or incompressible. One type of flowmeter is a vortexflowmeter which measures parameters including, for example, flow ratebased on the principle of vortex shedding. Vortex shedding refers to anatural process in which a fluid passing a bluff body (sometimesreferred to as a shedder) causes a boundary layer of slowly moving fluidto be formed along the surface of the bluff body. A low pressure area iscreated behind the bluff body and causes the boundary layer to roll up,which generates vortices in succession on opposite sides of the bluffbody. The frequency of the vortices is related to the flow rate. Thus,flow rate can be measured by detecting the vortices. For example, thevortices are associated with pressure variations in the fluid that maybe detected by a pressure sensor.

The vortex frequency data can be used in conjunction with flowcalibration factors to determine the velocity and volumetric flow rateof the fluid passing through the meter. If fluid density is known, themass flow rate can also be computed. These measurements, and others, canbe transmitted to a control room or other receiver over a communicationline, such as, for example, a standard two-wire 4-20 milliamp (“mA”)transmission line.

It has been recognized that the amplitude of the pressure oscillationsassociated with the vortices is related to the density of the fluid. Inparticular, if all other variables are equal a higher density fluid willresult in increased amplitude in the oscillating pressure signal frominside the vortex meter. Moreover, the amplitude of the pressureoscillation is to a large extent proportional to the product of thefluid density and the square of the fluid velocity. There have beenattempts to use this relationship between amplitude and density tocalculate mass flow directly by combining a density measurement derivedfrom analysis of the amplitude of the oscillation in the pressure signalwith the ordinary volumetric flow measurement provided by standardvortex metering techniques. However, the results of these efforts haveso far been unsatisfactory, apparently due to inability to limit errorin the density measurement to satisfactory levels.

Vortex flowmeters have to be calibrated and configured for optimalperformance in a particular application. In a typical scenario, when acustomer orders a vortex flowmeter, the customer provides some basicinformation about the intended use of the vortex meter. For example, theinformation may include the type of fluid (e.g., liquid or gas), normaland maximum expected flow rate, normal and maximum expected temperature,normal and maximum pressure, expected density, expected viscosity, etc.The vortex meter is configured to optimize operation of the meter in theintended application based on the information provided. Although avortex meter can operate with a wide range of fluid types and in a widevariety of conditions, a vortex meter may not provide accuratemeasurement if the configuration of the vortex meter does not match theapplication in which it is used. Vortex meters can be configured by thevendor based on information provided by the customer about the specificapplication for which the meter is intended. Alternatively, vortexmeters can be configured or reconfigured in the field. For example,handheld device communicators can be connected to a vortex meter toconfigure or reconfigure the meter.

However, there can be errors in the configuration for various reasons.For example, a vortex meter that is actually installed in a liquid lineand which is supposed to be measuring flow of a liquid may accidentallybe configured or reconfigured for use measuring flow rate of gas orsteam. Similarly, a vortex meter that is installed in a gas line may beaccidentally configured for use with a liquid. In either case, this mayresult in inaccurate measurement of flow by the vortex meter, which maynot be readily apparent in some circumstances. Another type of errorthat can occur is there can be an error in a process or system thatcauses the wrong type of fluid to flow through a fluid line. Forinstance, a liquid line may be emptied of liquid (e.g., due to a liquidtank running empty or a leak). Similarly, a gas line may be flooded withliquid. In either case, the presence of the wrong type of fluid in afluid line can be indicative of a problem that requires attention.

The present inventors have developed improvements to a vortex flowmeterthat facilitates reliable configuration the vortex meter. The presentinventors have also developed improvements to the ability of a vortexmeter to provide information about the fluid flow monitored by themeter, including rapid updates about any changes in the fluid. Theimprovements are more fully outlined and described in detail below.

SUMMARY

One aspect of the invention is a method of configuring a vortexflowmeter. The method includes flowing a fluid through the vortex meterin a manner that produces a series of vortices in the fluid. A pressuresensor is used to obtain a signal indicative of a time-varying fluidpressure having an oscillation associated with the vortices. Anamplitude of the oscillation of time-varying signal is determined andthe vortex meter is configured to have a fluid-type setting that isbased on said amplitude.

Another aspect of the invention is an alarming system for a controlsystem including a vortex flowmeter of the type having a flowtube, abluff body positioned in the flowtube for shedding vortices in a fluidwhen the fluid flows through the flowtube, and a pressure sensorpositioned to obtain a signal indicative of a time-varying fluidpressure having an oscillation associated with the vortices. Thealarming system includes a processor configured to determine anamplitude of the oscillation and to use the amplitude to assess adensity of a fluid flowing through the flowtube. The processor isfurther configured to compare the assessed density of the fluid to afluid density configuration setting of the vortex meter and activate analarm when the difference between the assessed density and the fluiddensity configuration setting exceeds a threshold.

Yet another aspect of the invention is a vortex flowmeter. The vortexflowmeter has a flowtube, a bluff body positioned in the flowtube forshedding vortices in a fluid when the fluid flows through the flowtube,and a pressure sensor configured to obtain a signal indicative of atime-varying fluid pressure having an oscillation associated with thevortices. The vortex flowmeter has a processor configured to determine afrequency of the oscillation and an amplitude of the oscillation. Theprocessor is further configured to determine a type of fluid flowingthrough the flowtube based on the amplitude of the oscillation andactivate an alarm when the type of fluid flowing through the flowtubedoes not match a configuration setting of the vortex flowmeter for fluidtype.

Still another aspect of the invention is a configuration tool for avortex flowmeter of the type having a flowtube, a bluff body positionedin the flowtube for shedding vortices in a fluid when the fluid flowsthrough the flowtube, and a pressure sensor configured to obtain asignal indicative of a time-varying fluid pressure having an oscillationassociated with the vortices. The configuration tool includes aprocessor configured to determine a type of fluid flowing through theflowtube based on the amplitude of the oscillation and to set afluid-type setting of the vortex meter to match the determined type offluid.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one embodiment of a vortex flowmeter;

FIG. 2 is a schematic diagram of another embodiment of a vortexflowmeter;

FIG. 3 is a schematic diagram of another embodiment of a vortexflowmeter;

FIG. 4 is a schematic diagram of one embodiment of an oil and gasseparation system including the vortex flowmeter; and

FIG. 5 is a flow diagram illustrating one embodiment of a method of thepresent invention.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring now to the drawings, first to FIG. 1, one embodiment of avortex meter for measuring fluid flow rate is generally designated 101.The vortex meter 101 includes a flowtube 103 through which a fluid canflow. The flowtube 103 is suitably configured for installation in afluid flow line (not shown). For example, process connections 105 (e.g.,flanges) are on the opposite ends of the flowtube 103 for connecting theinlet 107 and outlet 109 of the flowtube to the ends of pipes in apipeline. It is also common in the industry to use a so-called waferconnection to install a flowmeter in a fluid line and the flowtube canbe adapted for a wafer connection (or any other type of connection) ifdesired.

A bluff body 121 (sometimes referred to in the industry as a vortexshedder or shedder bar) is positioned in the flowtube 103. The bluffbody 121 is a structure that partially obstructs fluid flow through theflowtube 103 for the purpose of generating vortices in the fluid whenthe fluid flows through the flowtube. The vortex meter 101 includes apressure sensor 123 configured to obtain a signal indicative of atime-varying fluid pressure having an oscillation associated with thevortices. As illustrated in FIG. 1, for example the pressure sensor 123is suitably a differential pressure sensor mounted on a trailing end ofthe bluff body 121 so that the sensor is exposed to pressure on eachside of the bluff body. The frequency of the vortices is generallyproportional to the velocity of the fluid for a relatively wide range offlow conditions. Because the cross sectional flow area of the flowtube103 is constant, the frequency of vortices is also proportional to thevolumetric flow rate. This phenomenon is well known to those skilled inthe art and need not be discussed in detail.

The vortex meter 101 has a processor 131 connected to the pressuresensor 123 and configured to receive a signal from the sensor that isindicative of the time-varying fluid pressure. The processor 131 isconfigured to determine a frequency of the oscillation. The processor131 is also configured to determine an amplitude of the oscillation. Theprocessor 131 is further configured to determine a type of fluid flowingthrough the flowtube based on the amplitude of the oscillation. Forexample, the processor suitably determines whether the fluid is a gasphase fluid or a liquid phase fluid using the amplitude. If theprocessor 131 determines that the amplitude is above a threshold amount,for example, the processor determines that the fluid is liquid becausethe relatively high amplitude indicates a high density. Moreover, if theprocessor 131 determines that the amplitude is above a threshold, theprocessor determines that the fluid is not a gas. Conversely, theprocessor 131 suitably determines that the fluid is a gas and not aliquid when the amplitude is lower than a threshold amount at a givenfrequency. The thresholds may be different and/or there may beamplitudes of the signal from the pressure sensor that are not clearlyindicative of liquid or gas. However, in the majority of applications,there will be little uncertainty because of the large difference indensity of most liquids and gases.

As illustrated in FIG. 1, the processor 131 is configured (e.g.,programmed) to be (or is a component of) a configuration tool 133 thatfacilitates configuration of the vortex flowmeter 101. For example, theconfiguration tool 133 is suitably a device type manager (DTM). Thoseskilled in the art understand a DTM is a standardized driver for fielddevices that are used in distributed control systems. DTMs must maintaininteroperability so field devices from any device manufacturer can beused in conjunction with distributed control systems (or componentsthereof) from other manufacturers. It is understood, however, that theconfiguration tool does not have to be a DTM and other types ofconfiguration tools are possible. The configuration tool 133 andprocessor 131 are suitably located within the housing of a transmitterfor outputting information from the vortex flowmeter 101 about the flowrate of fluid through the flowtube 103 to a distributed control system.Alternatively, as illustrated in FIG. 2, the configuration tool 133 andprocessor 131 are suitably components of a hand held device that can beconnected to the vortex flowmeter 101 for use by a technician. Stillanother possibility is that the configuration tool 133 and processor 131are components of a remote device, such as a controller of a distributedcontrol system (FIG. 3).

The configuration tool 133 is suitably configured to set a fluid-typesetting of the vortex meter to match the determined type of fluid basedon analysis of the amplitude of the signal from the sensor 123. This canreduce the amount of time required to configure the vortex flowmeter 101during initial installation and/or verify a factory configuration is setproperly.

Although there are times, such as during initial installation of theflowmeter 101, when it may be desirable for the processor 131 to set afluid-type setting to match the determined type of fluid, there areother times when it may not be desirable to set a fluid type setting tomatch the determined type of fluid. The processor 131 is suitably alsoconfigured to activate an alarm when it determines the type of fluidflowing through the flowtube 103 does not match a configuration settingof the vortex flowmeter 101 for fluid type. For example, the processor131 suitably activates an alarm during initial installation of thevortex flowmeter 101 if the determined fluid type does not match thefactory setting, either in addition to or instead of setting the fluidtype setting of the flowmeter 101 to match the determined fluid type.

To provide another example, a problem with a process controlled by acontrol system (e.g., a distributed control system) including the vortexmeter 101 can result in the wrong type of fluid flowing through thevortex meter. Accordingly, the processor 131 is suitably configured asan alarming system for a control system including the vortex flowmeter101. The alarming system 131 is suitably configured to activate an alarmwhen the determined fluid type does not match the type of fluid that issupposed to flow through the flowtube 103. As another example, thealarming system 131 is suitably configured to compare the assesseddensity of the fluid (based on the amplitude of the signal from thesensor 123) to a fluid density configuration setting of the vortex meterand activate an alarm when the difference between the assessed densityand the fluid density configuration setting exceeds a threshold. Thiscan be desirable, for example, when the fluid that flows through theflowmeter 101 during normal operation has a limited density range.

Those skilled in the art understand distributed control systems havevarious standardized protocols for receiving alarms from field devicessuch as the vortex meter 101, transmitting and recording informationabout alarms that are received, displaying information about alarms, andpossibly taking corrective action in response to alarms. For example,the processor 131 and/or distributed control system is suitablyconfigured to associate the alarm with a function block running in thedistributed control system. The function block can be configured toimplement a process plant control algorithm based at least in part oninformation received from the vortex flowmeter. To provide anotherexample, the alarming system 131 is suitably configured to cause thetransmitter 135 to output a heartbeat value as an alarm. In general, aheartbeat value is a pulse output at a rate that is outside thefrequency range for a valid measurement. For example, the pulse outputcan have a frequency similar to a human heartbeat. Additionalinformation about outputting a heartbeat value as an alarm is providedin U.S. Pat. No. 8,576,084, the contents of which are herebyincorporated by reference.

The vortex flowmeter 101 can be used in any application that is suitablefor conventional vortex flowmeters. Some specific examples will bedescribed for further illustration, but other applications areunderstood to be within the broad scope of the invention. FIG. 4 showsthe vortex meter 101 installed in a fluid line for conveying liquid awayfrom an oil and gas separator 151. During normal operation of theseparator 151 all of the liquid leaves the separator through a liquidline 153 and all of the gas leaves the separator through a gas line 155.However, in some circumstances the separator may be completely empty ofliquid, which can result in gas carry-under—meaning gas is flowingthrough the liquid line 153. The processor 131 of the vortex meter 101is suitably configured to detect gas carry-under by monitoring theamplitude of the signal from the sensor 123. If the amplitude dropsbelow a threshold value the alarming system 131 suitably outputs analarm (e.g., outputs a heartbeat value). In this case, one wouldnormally not want the processor 131 to change the fluid typeconfiguration setting from liquid to gas because the gas carry-under isexpected to be a temporary condition and the typical response is to takecorrective action to restore normal operation of the separator as soonas possible. FIG. 4 also shows another vortex meter 101′ that issubstantially identical to the vortex meter 101 installed in the gasline 155 to detect liquid carry-over in the gas line by monitoring theamplitude of the signal from the pressure sensor 123 for any increasesin the amplitude that would indicate liquid instead of gas is flowingthrough the gas line.

To provide another example, the vortex meter 101 is suitably installedin a fluid line conveying wet steam. The vortex meter 101 is suitably amultivariable vortex meter configured to measure mass flow rate of fluidthrough the flowtube 103. When the vortex meter 101 is used in thisapplication, it is expected that the phase of the fluid flowing throughthe flow tube may change from time to time (or the relative amounts ofwater and steam) depending on how much heat energy is depleted from thesteam. Accordingly, the processor 131 is suitably configured to adjustthe manner in which the vortex meter 101 calculates a fluid flow ratemeasurement based on the amplitude of the signal from the pressuresensor 123. For example, the processor 131 is suitably configured toadjust a fluid density setting of the vortex flowmeter based on theamplitude of the signal from the sensor 123. This adjustment can beperformed by the processor 131 with or without alarms, depending on whatis desired for the specific application.

One embodiment of a method of the present invention is illustrated inFIG. 5. Fluid is flowed through the vortex meter 101 in a manner thatproduces a series of vortices in the fluid. The pressure sensor 123 isused to obtain a signal indicative of a time-varying fluid pressure inthe flowtube having an oscillation associated with the vortices. Theprocessor 131 determines the amplitude of the oscillation oftime-varying signal from the sensor and configures the vortex meter 101to have a fluid-type setting that is based thereon. For example, thefluid-type setting is suitably set to liquid if the amplitude isrelatively high and set to gas if the amplitude is relatively low. Themethod optionally includes adjusting a configuration setting for fluiddensity based on the amplitude. In particular, the fluid density settingis set relatively high if the amplitude is relatively high and is setrelatively low if the amplitude is relatively low.

The processor 131 suitably uses additional information to determine thedesired configuration setting. For example, it may be desirable in somecircumstances to determine a configuration setting for the vortex meter101 based in part on a temperature measurement. The temperaturemeasurement may be obtained from a temperature sensor that is includedin the vortex meter or from a separate temperature sensor.

The processor 131 and configuration tool 133 are suitably capable ofconfiguring the vortex meter automatically. For example, the processor131 and configuration tool 133 suitably automatically configure thevortex meter for use with a specified type of fluid based on theamplitude of the signal from the sensor 123 without any humanintervention during the process of configuring the vortex meter for usewith the specified type of fluid. For example, if a factoryconfiguration setting for fluid type does not match the amplitude-basedfluid-type determination, the processor 131 suitably automaticallychanges the configuration without any human intervention. The processor131 optionally activates an alarm if it automatically changes aconfiguration setting. Alternatively, the processor 131 suitablyactivates an alarm if a factory configuration setting for fluid typedoes not match the amplitude-based fluid-type determination and changesthe configuration only in response to a user input.

Furthermore, the method suitably includes monitoring the amplitude ofthe oscillation of the time-varying signal during use of the vortexmeter (e.g. as a field instrument in a distributed control system). Ifthe processor 131 determines that an incorrect fluid type is flowingthrough the vortex flowmeter 101 based on a change in the amplitude, itsuitably activates an alarm that indicates an incorrect type of fluid isflowing through the vortex flowmeter.

Although the systems and methods described herein refer to a processor,it is recognized that programs or other executable program componentsassociated with the systems and methods described herein may reside atvarious times in different storage components of a computing device.Embodiments of the aspects of the invention may be described in thegeneral context of data and/or processor-executable instructions, suchas program modules, stored one or more tangible, non-transitory storagemedia and executed by one or more processors or other devices.Generally, program modules include, but are not limited to, routines,programs, objects, components, and data structures that performparticular tasks or implement particular abstract data types. Aspects ofthe invention may also be practiced in distributed computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network. In a distributed computingenvironment, program modules may be located in both local and remotestorage media including memory storage devices.

In operation, processors, computers and/or servers may execute theprocessor-executable instructions (e.g., software, firmware, and/orhardware) to implement aspects of the invention. Embodiments of theaspects of the invention may be implemented with processor-executableinstructions. The processor-executable instructions may be organizedinto one or more processor-executable components or modules on atangible processor readable storage medium. Aspects of the invention maybe implemented with any number and organization of such components ormodules.

The order of execution or performance of the operations in embodimentsof the aspects of the invention illustrated and described herein is notessential, unless otherwise specified. That is, the operations may beperformed in any order, unless otherwise specified, and embodiments ofthe aspects of the invention may include additional or fewer operationsthan those disclosed herein. For example, it is contemplated thatexecuting or performing a particular operation before, contemporaneouslywith, or after another operation is within the scope of aspects of theinvention.

When introducing elements of the present invention of the preferredembodiments thereof, the articles “a”, “an”, “the”, and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including”, and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the foregoing, it will be seen that the several objects ofthe invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

The invention claimed is:
 1. An alarming system for a control systemincluding a vortex flowmeter of the type having a flowtube, a bluff bodypositioned in the flowtube for shedding vortices in a fluid when thefluid flows through the flowtube, and a pressure sensor positioned toobtain a signal indicative of a time-varying fluid pressure having anoscillation associated with the vortices, the system comprising: aprocessor; and storage media storing one or more configuration settingsfor the vortex flowmeter, the configuration settings including a fluiddensity configuration setting indicating a density of fluid that isexpected to flow through the vortex flowmeter, the storage media furtherstoring processor-executable instructions that, when executed by theprocessor, configure the processor to: determine a frequency of theoscillation and an amplitude of the oscillation based on the signalindicative of the time-varying fluid pressure obtained by the pressuresensor, assess a density of a fluid flowing through the flowtube basedon the amplitude, compare the assessed density of the fluid to the fluiddensity configuration setting of the vortex meter, activate an alarmwhen the difference between the assessed density and the fluid densityconfiguration setting exceeds a threshold, and output a flowratemeasurement based on the determined frequency of the oscillation and theconfiguration settings stored in the storage media when the differencebetween the assessed density and the fluid density configuration settingis less than the threshold.
 2. An alarming system as set forth in claim1 wherein the control system is a distributed control system and theprocessor is further configured to associate the alarm with a functionblock running in the distributed control system, the function blockbeing configured to implement a process plant control algorithm based atleast in part on information received from the vortex flowmeter.
 3. Analarming system as set forth in claim 1 wherein the processor is locatedin a transmitter housing containing a transmitter configured to output afluid flow rate measurement from the vortex meter.
 4. An alarming systemas set forth in claim 1 wherein the control system is a distributedcontrol system and the processor is located in a controller of thedistributed control system that is configured to receive a fluid flowrate measurement from the vortex meter.
 5. An alarming system as setforth in claim 1 wherein the vortex meter is installed in a fluid linefor conveying liquid away from an oil and gas separator.
 6. An alarmingsystem as set forth in claim 5 wherein the alarm comprises outputting aheartbeat value in response to gas carry-under in the fluid line.
 7. Analarming system as set forth in claim 1 wherein the vortex meter isinstalled in a fluid line conveying steam.
 8. An alarming system as setforth in claim 1 wherein the processor is further configured to adjustthe manner in which the vortex meter calculates a fluid flow ratemeasurement based on the amplitude of said oscillation.
 9. An alarmingsystem as set forth in claim 8 wherein the vortex meter is amultivariable vortex meter configured to measure mass flow rate of fluidthrough the flowtube.
 10. An alarming system as set forth in claim 1wherein the processor is further configured to adjust a fluid densitysetting of the vortex flowmeter based on said amplitude.
 11. An alarmingsystem as set forth in claim 1 further comprising a device type manager.12. An alarming system for a control system including a vortex flowmeterof the type having a flowtube, a bluff body positioned in the flowtubefor shedding vortices in a fluid when the fluid flows through theflowtube, and a pressure sensor positioned to obtain a signal indicativeof a time-varying fluid pressure having an oscillation associated withthe vortices, the system comprising: storage media for storingconfiguration settings for the vortex flowmeter, the configurationsettings including a fluid type setting indicating a type of fluid thatis expected to flow through the vortex flowmeter; and one or moreprocessors configured to determine based on the signal a frequency ofthe oscillation and an amplitude of the oscillation, the one or moreprocessors being further configured to, at a flow rate measurement time:determine a type of fluid flowing through the flowtube based on theamplitude of the oscillation, compare the determined type of fluidflowing through the flowtube to a type of fluid that is expected to flowthrough the flowtube in a process in which the vortex flowmeter isinstalled, output a flowrate measurement based on the determinedfrequency of the oscillation and the configuration settings stored inthe storage media when the determined type of fluid is the type of fluidthat is expected to flow through the flowtube in the process in whichthe vortex flowmeter is installed, and activate an alarm when thedetermined type of fluid differs from the type of fluid that is expectedto flow through the flowtube in the process in which the vortexflowmeter is installed; wherein at a configuration time before the flowrate measurement time, the one or more processors are configured todetermine the fluid type setting based on the determined amplitude ofoscillation and a temperature measurement representative of atemperature of a fluid flowing through the flowtube and to store thefluid type setting in the storage media.
 13. An alarming system as setforth in claim 12 wherein the one or more processors are located in atransmitter housing containing a transmitter configured to outputinformation from the vortex meter about the rate of fluid flow throughthe flowtube.
 14. An alarming system as set forth in claim 12 wherein atleast one of the one or more processors is part of a portable handheldunit connected to the vortex flowmeter.
 15. An alarming system as setforth in claim 12 wherein the control system is a distributed controlsystem and the at least one of the one or more processors is furtherconfigured to associate the alarm with a function block running in thedistributed control system, the function block being configured toimplement a process plant control algorithm based at least in part oninformation received from the vortex flowmeter.
 16. An alarming systemas set forth in claim 12 wherein the control system is a distributedcontrol system and the at least one of the one or more processors islocated in a controller of the distributed control system that isconfigured to receive a fluid flow rate measurement from the vortexmeter.
 17. An alarming system as set forth in claim 12 furthercomprising a device type manager.
 18. A method of alarming for use witha control system including a vortex flowmeter of the type having aflowtube, a bluff body positioned in the flowtube for shedding vorticesin a fluid when the fluid flows through the flowtube, and a pressuresensor positioned to obtain a signal indicative of a time-varying fluidpressure having an oscillation associated with the vortices, the methodcomprising: determining a frequency of the oscillation and an amplitudeof the oscillation based on the signal indicative of the time-varyingfluid pressure obtained by the pressure sensor, assessing a density of afluid flowing through the flowtube based on the amplitude, comparing theassessed density of the fluid to a fluid density configuration settingof the vortex meter, the fluid density configuration setting indicatinga density of fluid that is expected to flow through the vortexflowmeter, activating an alarm when the difference between the assesseddensity and the fluid density configuration setting exceeds a threshold,and outputting a flowrate measurement based on the determined frequencyof the oscillation and the configuration settings stored in the storagemedia when the difference between the assessed density and the fluiddensity configuration setting is less than the threshold.
 19. A methodas set forth in claim 18 wherein the control system is a distributedcontrol system and further comprising associating the alarm with afunction block running in the distributed control system, the functionblock being configured to implement a process plant control algorithmbased at least in part on information received from the vortexflowmeter.
 20. A method as set forth in claim 18 wherein activating thealarm comprises outputting a heartbeat value in response to gascarry-under in the fluid line.